The present invention relates to a turntable drive mechanism in a cooking oven, such as an oven, a microwave oven or the like.
A typical turntable drive mechanism in a cooking oven, such as an oven, a microwave oven or the like, conventionally has a drive motor arranged outside the oven, i.e. outside a cooking chamber in which the turntable is disposed, with a revolving shaft of the drive motor penetrating through a wall of a heating chamber to be coupled to a revolving shaft of the turntable.
However, such a motor shaft projecting inside the oven has been problematic in that it causes inconvenience upon washing the interior of the oven. Further, the through hole formed in the wall of the oven for inserting the motor shaft therethrough has made it impossible to wash the oven interior with water. Still further, there has been another problem that the oily stain accumulated on the motor shaft portion is likely to lock the motor and to obstruct a regular operation thereof, which would result in a breakdown.
Besides, there has been still another problem that when the rotary movement of the turntable is constrained for some reason, it probably leads to the breakdown of the motor which has been mechanically coupled directly with the turntable.
In addition to the above problems, for the microwave oven, the microwave heating oven or the like, which has employed a microwave heating, it has been required a preventive measure to be taken for preventing the microwave from leaking through the penetrating portion for the motor shaft.
An object of the present invention is to provide a turntable drive mechanism of a cooking oven, which can solve the problems associated with the prior technology as described above.
A turntable drive mechanism according to the present invention comprises: a support member for rotatably supporting a turntable within a cooking chamber of a cooking oven; a driver unit arranged outside said cooking chamber for rotationally driving said turntable; and a magnetic coupling arranged between a revolving shaft of said turntable and another revolving shaft of said driver unit, wherein said magnetic coupling is composed of: a first coupling member attached to said revolving shaft of said driver unit and having magnets arranged so as to provide a surrounding of said revolving shaft with magnetic poles of alternately different polarities; and a second coupling member attached to said revolving shaft of said turntable and having magnets arranged so as to provide a surrounding of said revolving shaft with magnetic poles of alternately different polarities, said first and said second coupling members being adapted to face each other with a non-magnetic wall portion defining said cooking chamber sandwiched therebetween.
According to an embodiment of the present invention, each of said first coupling member and said second coupling member comprises a plurality of magnets contained within a nonmagnetic case having a revolving shaft coupling portion which is to be coupled to either of said revolving shaft respectively.
According to another embodiment of the present invention, each of said first coupling member and said second coupling member comprises a magnet, which has been polarized to include a specified number of poles, contained within a non-magnetic case having a revolving shaft coupling portion, which is to be coupled to either of said revolving shaft respectively.